Fingerprints

Fingerprinting has always been used, but it wasn’t until modern times that it was used for identification. In ancient Persia fingerprints were used to sign documents and were continued to be used as a way for singing contracts for many years. It wasn’t until 1880 that the importance of fingerprints for identification was realized by Dr. Henry Faulds. Even with Faulds research the Bertillon method of identification more popular. The Bertillon method of identification was involved by Alphonse Bertillon and involved taking the measurements of a person to identify them. Finger prints were used as a secondary means of identification until a man was wrongly jailed because he shared similar measurements with his twin brother. From that point on fingerprints were used as a primary means of identification. In 1892 Joan Vucetich was the first to use fingerprints in a criminal investigation identifying a murderer. Through out the years finger printing became more common being adopted by US prisons, the Army, the Navy and the Marines. As finger printing spread hundreds of millions fingerprint cards were made around the world. To keep track of criminals and citizens alike automated systems, such as AFIS (1946), were created around the world. The FBI posseses the largest AFIS system and all states will posses their own AFIS systems. Today fingerprinting is an invaluable in the fight against criminals world wide.

There three types of fingerprints, direct, latent and plastic. A direct fingerprint is visible because it is usually left in one of these mediums: grease, dirt, blood, ink, or paint and does not require dusting before lifting the print.

A latent print is not visible to the naked eye and is usually left on either dark or glass surfaces. To lift a latent print on glass a darker powder, such as black carbon, is required when dusting to see the contrast before lifting. On a dark surface a lighter dusting powder, such as aluminum powder, is required to see the contrast before lifting.

Finally plastic prints are ridge impressions and impressed into a soft medium such as wax, putty, soap, or dust.

Besides darker and lighter powders like black carbon powder and aluminum powder there are other techniques and chemicals to lift prints, such as magnetic-sensitive powders, fluorescent powders, and the iodine fuming process. The different types of prints and different locations of the prints require different chemicals and techniques. For latent prints iodine fuming and fluorescent powders are most effective. Powders should be used when the surface is a dark hard surface lighter powders should be used and for glass surfaces darker powders should be used. For softer surfaces chemicals should be used.

(These are the eight types of finger prints).


Sources:
http://www.bxscience.edu/publications/forensics/articles/fingerprinting/f-fing03.htm http://odec.ca/projects/2004/fren4j0/public_html/types_prints.htm http://www.onin.com/fp/fphistory.html

Hand Writing

At its base hand writing analysis for forensic purposes is simple: by comparing samples of the same hand writing it can be determined if it is authentic or a forgery. This possible because to a trained professional hand writing is like finger prints; unique to the individual.

(Free hand copy of
my hand writing)
Graphology can be considered the forerunner of forensic hand writing analysis. The two use similar components as a means of analysis. Although the two are similar hand writing analysis is based in science while graphology is based in psychology. Graphology started from the idea that hand writing originates in the brain and therefore can be used to create a psychological profile of the writer, while hand writing analysis is used for two main purposes. “One is to authenticate documents and other is used to link a suspect to a crime”1. Hand writing analysis seem basic but is actually very difficult because unlike finger prints writing can’t be broken down into eight specific classifications, it is built on comparative analysis on the premise of twelve characteristics. They are line quality, spacing of words, size of letters, lifts of the pen, connection of strokes, beginning and ending of strokes, unusual latter formation, pen pressure, slant, baseline habits, fancy writing habits, and placement of diacritics. By using these characteristics forensic hand writing analysts are able to notice subtle differences in hand writing which allows them to authentic documents and exclude or include suspects in a criminal criminal investigation.

(Traced copy of my
hand writing)

(Free hand and traced copy of my handwritng in a ransom note)

Sources:
(1) http://www.enotes.com/forensic-science/handwriting-analysis
http://forensicscience.suite101.com/article.cfm/forensic_or_scientific_handwriting_analysis